WO 2012/077617 (PTD 1), and Japanese Patent Laying-Open Nos. 2012-99601 (PTD 2) and 2013-69964 (PTD 3), for example, each disclose a silicon carbide semiconductor device including a p type diffusion layer formed in a lower portion of a trench.
Japanese Patent Laying-Open No. 2013-145770 (PTD 4) discloses a silicon carbide semiconductor device having a deep p type region formed in a source region. Japanese Patent Laying-Open No. 2014-41990 (PTD 5) discloses a silicon carbide semiconductor device having a buried p type region.